This invention relates to the display of a cursor pattern on electrical image processing equipment. More particularly, the invention provides a selectable and flexible cursor overlay on a displayed visual image, without disturbing the storage of the original image information.
Electrical image processing equipment is known which displays a program-selectable cursor with the display of image information. In one instance of bit-mapped graphic display equipment using a CRT display, the cursor information is combined with the image information during the preparation of each video field. The Alto computer system of Xerox Corporation is understood to employ such a cursor system. Aspects of that computer system are described in U.S. Pat. No. 4,103,331 entitled "Data Processing Display System"; U.S. Pat. No. 3,911,419 entitled "Controller for Cursor Positioning On A Display Medium"; U.S. Pat. No. 3,892,963 entitled "Transducer For A Display Oriented Pointing Device"; U.S. Pat. No. 3,898,377 entitled "Video Mixer"; U.S. Pat. No. 4,148,098 entitled "Data Transfer System With Disk Command Verification Apparatus"; and U.S. Pat. No. 4,103,330 entitled "Task Handling In A Data Processing Apparatus".
Also in the prior art is the disclosure in U.S. Pat. No. 4,345,313 entitled "Image Processing Method And Apparatus Having Digital Airbrush For Touch Up". That patent describes an image system which selectively increases and decreases the portion of a graphics display at a cursor position.
It is an object of this invention to provide apparatus and a method for the improved display of a cursor pattern on electronic image processing equipment. One particular is to improve the flexibility and the control of the display.
A further object of the invention is to provide such an improved display of a cursor pattern on electronic image processing equipment without disturbing the storage of the image information being displayed.
Another object of the invention is to attain the foregoing method and apparatus with relatively little modification of existing image processing equipment.
Other objects of the invention will in part be obvious and will in part appear hereinafter.